Engines may utilize various cooling jackets in the head and block to provide cooling. However, there may be competing objectives for the cooling system relating to increase engine efficiency and waste heat rejection, improving engine warm-up, maintaining peak temperature control, providing cabin heating, etc.
One approach to balance such objectives includes an engine method, comprising:
pumping coolant from a pump output, in parallel, directly to a block and a head upper coolant jacket;
flowing coolant from the block directly to a head lower coolant jacket;
discharging coolant from the upper and lower jackets only to a control block; and
selectively directing cooling from the control block to each of: a cabin heater; radiator bypass line; and the radiator.
For example, it may be possible for a coolant-operated cabin heater to be provided with coolant that has been pre-warmed in the cylinder block. In this way, an increased demand for pre-warmed coolant can be met, for example in the case of low outside temperatures. In this way, all of the coolant conducted through the cylinder head and through the cylinder block can be connected via the heating circuit line to an inlet side of the control block.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.